Laser induced breakdown spectroscopy (LIBS) is a type of atomic emission spectroscopy which uses a highly energetic laser pulse as the excitation source. The laser pulse generates high temperature micro plasma on the surface of the sample. After this excitation, light that is characteristic of the elemental composition of the sample is emitted and analyzed within a spectrometer. LIBS has become a very popular analytical method in view of some of its unique features such as applicability to any type of sample, practically no sample preparation, remote sensing capability, and speed of analysis.
A LIBS spectrum is composed of a plurality of atomic (ionic) emission lines, each corresponding to one element in the sample. LIBS is more sensitive to elements with low ionization energies for which more atoms are excited in response to a particular energy input. It is less sensitive to elements with high ionization energies, such as halogen and chalcogen elements. These elements produce much less and weaker emission lines than elements with prominent peaks such as alkalis, alkaline earth elements, and transition metals. Thus they make much less ‘contribution’ to the overall LIBS spectrum. This characteristic renders commonly used spectrum identification and library search algorithms less effective when applied to LIBS spectra as the spectral features of those ‘weak’ elements are often neglected.